Egypt's army said it would seek to take legal action against former anti-corruption chief Hisham Geneina and former military chief-of-staff Sami Anan following Geneina's claims that Anan possesses documents containing state secrets that could convict many officials if revealed.

Geneina was a leading figure in Anan's brief presidential campaign before the former military chief was barred from running in a March presidential vote and was detained by authorities last month, a week after announcing his candidacy.

In an interview with HuffPost Arabia published on Sunday, Geneina claimed that Anan possessed documents and evidence relating to major deadly incidents and "political crimes" since the 2011 revolution and following the 2013 ouster of Islamist president Mohamed Morsi. He said the documents were kept abroad and would surface if authorities tried to assassinate Anan, whom the army has accused of breaching laws by running for office without its consent.

The army said in a statement on Monday that Geneina's claims "amount to crimes and aim to raise doubts about the state and its institutions" at a time when the armed forces are waging a battle to uproot terrorism in the Sinai region."

It said it would refer the matter to investigators with a view to taking the necessary legal action against both Geneina and Anan, and that it would "use all constitutional and legal powers to preserve national security."

An hour after the army's statement, Anan's lawyer Nasser Amin distanced his client from Geneina's controversial remarks.

In a statement on Facebook, he described the claims as "unfounded, untrue and bearing no relation to reality."

The lawyer pledged to take legal action against anyone who has given or will give statements to the media "attributing any words or acts to Anan that would undermine [Anan's] legal status or expose him to the danger of legal or social liability."

"Any statements not made by Sami Annan in person are attributed to their owners and do not in any way express him," he said.

Anan was detained by authorities last month, a week after announcing his presidential bid. The army accused him of inciting against the military and breaking the law by running for office without its permission while still a reserve officer.

Geneina was attacked and severely wounded two weeks ago while on his way to lodge an appeal against an electoral commission's decision to disqualify Anan from running in the presidential vote, scheduled for 26-28 March. He said in media interviews that Egyptian authorities were behind his assault.

The interior ministry said at the time of the attack that Geneina hit a man with his car and that his doorman, wife and daughter assaulted what Geneina said were the attackers and tore off their clothes.